In Situ Electric-Field Guided Assembly of Ordered Bilayer Solid Electrolyte Interphase (SEI) Enables High-Current Zinc Metal Anodes

Aqueous zinc-ion batteries (AZIBs) face significant challenges at high current densities, where conventional single-layer solid electrolyte interphases (SEIs) dissolve or collapse under zinc volume fluctuations. We introduce an in situ synergistic decomposition strategy that constructs a mechanically adaptive bilayer SEI featuring a nitrogen-rich amorphous carbon outer layer and a crystalline ZnF 2 /ZnCO 3 inner layer. This architecture forms through controlled decomposition of iminodiacetic acid and zinc trifluoromethanesulfonate at the inner Helmholtz plane, combining Zn 2+ conductivity, hydrophilicity, and electrical insulation with robust corrosion resistance. The resulting bilayer SEI enables dendrite-free zinc plating at high current densities, achieving >1690 h at 10 mA cm –2 and >667 h at 30 mA cm –2 with cumulative capacity exceeding 10 Ah cm –2 . Furthermore, it supports stable operation under deep stripping (89% depth of discharge for 140 h in Zn||Zn) and long-term cycling (4500 cycles at 5 A g –1 in Zn||V 2 O 5 ). This ordered bilayer SEI, constructed from a unique in situ synergistic excitation process, provides a generalizable framework for mechanically adaptive interface engineering, advancing the development of fast-charging and high-power AZIBs.